多线程下载多张图片

1.继承thread

2.重写run()

3.创建线程对象，调用start（）启动线程

线程不一定立即执行，cpu安排调度

①导包，右键make as library

②

package com.wuming.demo01;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;
import java.net.URL;

//练习Thread，实现多线程同步下载图片
public class TestThread2 extends Thread{
    private String url;//网络图片地址
    private String name;//保存的文件名
    public TestThread2(String url,String name){
        this.url=url;
        this.name=name;
    }
    //下载图片线程的执行体
    @Override
    public void run() {
        webDownloader webDownloader = new webDownloader();
        webDownloader.downloader(url,name);
        System.out.println("下载的文件名为："+name);
    }
    public static void main(String[] args) {
        //ctrl+d快速复制三行
        TestThread2 t1 = new TestThread2("https://lmg.jj20.com/up/allimg/tp09/210611094Q512b-0-lp.jpg","1.jpg");
        TestThread2 t2 = new TestThread2("https://lmg.jj20.com/up/allimg/tp09/210611094Q512b-0-lp.jpg","2.jpg");
        TestThread2 t3 = new TestThread2("https://lmg.jj20.com/up/allimg/tp09/210611094Q512b-0-lp.jpg","3.jpg");
       //多线程同时下载多张图片，每次执行结果不一样，占cpu多就先执行
        t1.start();
        t2.start();
        t3.start();
    }
}
//下载器
class webDownloader{
    //下载方法
    public void downloader(String url,String name){
        try {
            FileUtils.copyURLToFile(new URL(url),new File(name));
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("IO异常，downloader方法出现问题");
        }
    }
}